Typically, a leisure vehicle, for example a motorcycle, is equipped with a rider's seat which is open to the outside. Thus, anyone may freely mount the rider's seat. A mechanical key is inserted into a key hole to turn on or off a main switch of the vehicle and is positioned in an exposed region near the rider's seat, for example, an instrument panel located in front of the rider's seat. As used herein, the term “mechanical key” refers to a key that has a specified concave-convex shape in a teeth portion to enable mechanical unlocking and does not have a function of transmitting a user identification (ID) code and the like.
For the above reason, the motorcycle is more likely to be stolen in contrast to four-wheeled motor vehicles such as automobiles or trucks, which are equipped with drivers' seats isolated from outside in which a third party is unable to access.
Under the circumstances, a theft prevention apparatus equipped in the vehicle is disclosed, in which the mechanical key inserted into the key switch is operated to turn on the main switch equipped in the vehicle only when the theft prevention apparatus receives, from a portable device (card-type portable device) being carried by a user such as a rider, a user ID code that matches a user ID code stored in a memory built into the vehicle, and in this state, the rider can start-up an engine.
In the leisure vehicle such as the motorcycle, since the rider's seat is open to the outside as described above, the rider in many cases steers the motorcycle, wearing gloves while driving. To start the vehicle, the rider takes the gloves off to take the mechanical key out of the pocket or the like, inserts the mechanical key into the key hole, and rotates the key to a predetermined position. Thereafter, the rider puts back on the gloves. Such a procedure may be burdensome to the rider.
To address these circumstances, a new electronic theft prevention system is proposed which is not equipped with the key switch using the mechanical key (see Japanese Patent Application No. 2005-013581). The electronic theft prevention system includes a portable device configured to transmit a user ID code and an in-vehicle theft prevention apparatus that is configured to receive the user ID code transmitted from the portable device, determine whether or not the received user ID code matches a user ID code stored in a memory built into the vehicle, and turn on an electric circuit when it is determined that these two user ID codes match, thereby starting the vehicle. In this electronic theft prevention system, only a person carrying a specified portable device is able to steer the motorcycle without the use of the mechanical key. In addition, a main switch is fixedly mounted to the vehicle instead of the key switch and is rotated or pressed down to turn on and off the main switch or the like mounted to the vehicle. This electronic theft prevention system has advantages that the rider need not take the mechanical key out of a pocket or the like and insert it into the key hole every time the rider steers the vehicle. So, the rider need not take off gloves to take the mechanical key out of the pocket or the like.
However, in the leisure vehicle equipped with the above mentioned electronic theft prevention system, the rider needs to take the mechanical key out of the pocket or the like and unlock a lock device provided to a tank cap (also referred to as a fuel cap) to refill a fuel. The rider also needs to take the mechanical key out of the pocket or the like to lock or unlock a helmet holder or an article container. So, the rider needs to carry the mechanical key in the pocket or the like, but may in some cases forget to put the mechanical key in the pocket or the like because the mechanical key is not used to operate the main switch. In those cases, the rider recognizes that the rider is not carrying the mechanical key at the time of fuel refilling or unlocking of a helmet.